Three-dimensional (3-D) printing (also known as additive manufacturing or rapid prototyping) allows for the production of three-dimensional objects by building up a material on a layer-by-layer basis. One common 3-D printer employs a printhead extruding material and movable in three Cartesian axes (x, y, z) with respect to a print surface. Under the control of a computer, the printhead moves through a series of positions over the printing surface and at each location deposits a small volume of material to define a portion of the printed object at that location. After a base layer is printed directly on the printing surface, the printhead is successively elevated (z-axis) to print additional layers on top of the base layer and then each succeeding layer until the entire object is printed.
At least one of the printhead or print surfaces is typically supported on an x-y carriage having ways extending along one axis (e.g. the x-axis) that support a movable carriage with ways extending along the perpendicular axes (e.g. the y-axis). The position of the carriage along the first set of ways and the position of the printhead along the second set of ways is typically controlled by electric motors (stepping motors and/or DC servo motors) operating through lead screws, belts, or the like.
Fabrication of precision linear ways and the drive mechanism associated with the ways can be costly or difficult, particularly for large or very small systems. Further the fabrication process is normally slow, limited by the speed at which a single carriage holding one or more printheads can be maneuvered within the framework of the ways.